So it's time to dig into the carbs on the T bucket. It idles well, responds to idle speed and mixture adjustments, float levels are set properly. Seems to run well at steady RPM. The issue is tip in at all speeds, especially off idle. I'm not a neophyte on carbs, so I expect that the accel pump and squirters will need work. Unfortunately, I don't have all the specs for the engine or carbs. I will be gathering more info as I can, such as vacuum at different RPM in the hopes to get an idea of cam size without disassembly. I will also pull the squirters and note size. The accel cams are Pink. The basic engine is a ZZ3 crate small block Chevy made in 1989. It has been modified. It has roller rockers, head studs and a tunnel ram with 2 QFT carbs. It also sounds like it's cam is bigger than stock. MSD ignition and open long tube headers with no collectors. I have tried to ID these carbs so I have some idea what the out of the box setup is to compare to what it has now. https://www.holley.com/brands/quick_fuel/ does not provide list numbers and doing a search for the #s I have gets nowhere. I've done other web searches and had no success. The site does have tunnel ram carbs which seem to sort of match in overall basics. 4160 style, vacuum secondary. However, they do not have chokes, which are on the pair I have. The chokes are not connected or adjusted. This is a fair weather car. https://www.holley.com/products/fuel_systems/carburetors/street/parts/SL-450-VSTRF https://www.holley.com/products/fuel_systems/carburetors/street/parts/SL-450-VSTRR this is the basic 450, which matches mine more closely. Again, no LIST #s. https://www.holley.com/products/fuel_systems/carburetors/street/parts/SL-450-VS So the list #s on mine are 4507114 front, 4507108 rear. That prefix is why I expect them to be 450s. I've found many setup pages and videos, but would like to confirm ID of these as best as I can. Yes, both need to be removed and sprayed down. I hope to dig in a bit more when they are off, so I'd like to know what they are before I pull them off. Pictures... top front rear right side left side, pink cams visible. Also, front carb has a black sticker, rear has a white sticker.
You would have to take them apart and write down jet, shooter, power valve and throttle blade size then compare those numbers to the carbs you think they could be. I use all mechanical secondary carbs so I'd be no help but on the 450's in that series switching from the 30cc pump to 50cc pumps and cams eliminates all the bog, of course you could fine tune the shooter and jets afterwards if need be. Quick fuel carb breakdown pdf file https://www.quickfueltechnology.com.au/content/Quick Fuel Carb Size with details-AUST.pdf
Thanks, good info there. Still no list numbers or any that match these. I expect that documenting everything would be the next step, but I know there will be gasket tears, parts I'd like to swap and so on. Before I go in, I'll have to get a couple kits and have some parts handy. I figure at least half a day to pull, clean, disassemble, document, reassemble and fix any big issues and get them back on. The last time I did a tunnel ram, it was a car that could handle the power better, and I still didn't get into the secondarys much. This really has no use for this intake and carbs. A single 4 would be more than enough, but ya gotta love the look. The other car had a manual trans, too. I'd think 50cc pumps would be overkill for the engine size and RPM. 2 30cc ought to be able to be tuned for stroke and squirters. Never did like dumping too much, especially on hot starts, which is another symptom (long cranking hot after cracking throttle). I'll call them and Holley during business hours and try to get more.
Well, Jegs has a listing for just the cams at 22 bucks (back ordered) https://www.jegs.com/i/JEGS/555/150270/10002/-1 and have the full on kit for 200-250, also back ordered (speedway, too). https://www.jegs.com/i/JEGS/555/150270/10002/-1 I realize I only need one, then once I have a handle on what's needed, I can order just the single additional part(s) for the second carb, but that's on top of the basic gasket sets for 41 each. At that point, I might just look for a Victor Jr and a single 4 barrel used. https://inlandempire.craigslist.org/pts/d/murrieta-edelbrock-chev-small-block/7789755493.html That's why I want to ID what's expected first. I can pull the squirters and compare to 'factory' along with the cams before I start taking things apart.
That motor doesn't need a victor jr either, what you're failing to realize with the tunnel ram is that it has a tremendous volume of air that needs fuel mixed with it, more than just a shooter can provide. Here's a Holley cam graph to help you better understand what each is going to do Putting a bigger shooter in it is only going to deplete the small pump shot faster.
@swade, Thanks for the chart! I know it's like having a set volume of water in your mouth. You can dribble it out slowly, force it out quickly or somewhere in between. The car currently does not act like there is no accel pump, with a sharp drop and a sneeze. The squirt is pretty heavy and tapers off quickly. I'd guess it needs a bit smaller squirter to make it last a bit longer. The Blue or Green line looks like more what I'd want, the same or less at first, a bit more past tip in. Yeah, for good part throttle streetability, a Victor Jr is not the choice. I'd be better off with a Q-jet and a dual plane. This isn't getting loose converter, full throttle, high RPM blasts. Heck, a duojet would satisfy most use cases! But it is not getting a cast iron manifold and 2 bbl. I sure wouldn't do that and hide it under a fake blower or scoop.
@squirrel , I drove it Friday in 40 Degrees (4.4C for those who have metric brains)! Hands and face were chilly. Okay, frigid! Gloves are required. It took a bit to get it going, but it was fine after a bit of warm up. I'd rather tune the bog out first. @swade41 s chart will help a bunch, so hoping to do the edge case. Get a high RPM setup to be responsive and behave during low RPM transitional use at high altitude! And for my next trick, I'll get some Hilborns to purr! All that to say I know this is a fool's errand, but I'll work to get the best I can out of the setup, with an eye toward all the other things that need doing and budgeting across the whole thing. Yes, a pair of kits, full gasket sets and a jet and power valve assortment would make this simpler. That would also be the budget for a complete replacement intake and carb that would work better out of the box. I want to work with what's there because of the looks, the challenge, the pride once it's better and just being a contrary ol cuss. I want to thank you again Jim. The fan kept it cool!
Chino Valley is at 4700 ft, just like where I live. I consider it normal (if it runs OK here, it'll probably run OK everywhere else) What affect does leaving the idle mixture way too rich, have on tip in?
It's normal until your sea level friends come up and start panting! When I got it, it was 2 turns out all around (4 idle screws). It was pretty darn rich, but the tip-in was pretty much the same. I've got it at about 3/4 out all around now. I can give it a try, cheap and easy. My feeling is that it needs more squirter later, not a quick dump = smaller squirter, probably bigger cam. Make that lil spring work for a living! I'd just like to know what was 'factory' and how much if any previous tinkerers have changed things. It would be nice to know what the fine folk at QFT have for their own TR carbs. Learn from the experience of others rather than make the same mistakes myself. The 4160 and vacuum secondary design supports thinking smaller CFM and the list number starting with 450 appears to indicate 450s, but we know what happens when you assume. So being able to confirm they aren't a pair of 850s would be nice too.
Yep. This was just a long winded asking for an ID on them, so I knew what I was working with and why I wanted the info before diving in. I need to get a video of it for you and Swade. Gotta dig up my gloves! EDIT: Too bad it's cold, overcast and raining! I also realize that the cam isn't helping either. Feels like a typical performance grind, which means lower vacuum signal at low RPM, coming on at higher RPM. Bad for off idle manners. My previous experience was a 340 with a .509 lift, 292 advertised duration and tunnel ram. This one feels a bit smaller but not stock. Wild guess is around 480 lift, 280 duration, but haven't hooked up a vacuum gauge yet. It seems to start getting happy around 1500-1800 RPM, where the 340 smoothed out at 2200-2500. I will mention this is all by ear. No tach or speedo! Timing hasn't been checked with a light yet either. I'd want to verify TDC before believing any numbers. It does not kick back on the starter much hot, doesn't ping, and when up in the RPM it pulls very well, so it is close, to my ear. I doubt another couple degrees of initial is going to cover the bog.
Well then. Went out, got the tuneup kit out and did some basics. I have some videos in my T bucket album. https://www.jalopyjournal.com/forum/media/albums/t-bucket.48486/ One is a big long name which is from the ad before I got it. It looks like a cold start and not useful here.Does show it wasn't great when bought. https://www.jalopyjournal.com/forum...dtlvx4g-cpktgch-ouozditx-8bhacwwitaup.594767/ The following videos are after a few minutes of running. Not fully up to temp, but not dead cold either. Idle mix was adjusted again to best idle. No lean drop, no rich chug. Ended up with the cold temp being about 3/4 out all around. No video of this. I have one called MSDRPM. Shows the old meter isn't happy with MSD, showing 3500 at idle! My ear says around 1000-1100. https://www.jalopyjournal.com/forum/media/msdrpm.594772/ Next is TIM MARK, showing the timing mark is typical long water pump straight up with the scale on the left side of the timing cover. My old dial back Snap on timing light bulb is broken and they don't warranty it any more (15 years ago they didn't)! This forces me to verify TDC and get a timing tape. https://www.jalopyjournal.com/forum/media/tim-mark.594774/ Last one is RPM, I'm bringing the RPM to show how the cam gets happier at higher revs. https://www.jalopyjournal.com/forum/media/rpm.594773/ I have another on my phone that shows vacuum at idle (11") and how I had the timing set by ear. It is before advanced stumble, and more than retarded idle drop. The file is too large to load here and I don't have a youtube, so it's not available. You will have to take my word here. I'm wondering if the old gauge is telling the truth. At higher idle, say 1800, it's still showing 11 inches. When revved and released, it never goes above 16".
Vacuum gauges don't show big numbers at higher elevation, since there's less air pressure. I only see 4 videos on your album page, but you describe a couple more (without links). I don't see any in your post.
Just the 4. One with vacuum showing and turning the dist. is too big to load, so it's not in the folder but is described. No extra info really, just verifying that timing is in the ballpark and showing the vacuum gauge. Makes sense with the altitude. Haven't pulled it out of the box up here before. I didn't video the idle mixture process, it would take too long (big file) to turn all 4. I'll add edits to the post to clarify. I did take it out and blast it around the block in the rain. Fun stuff! Going to pay for it having to wipe down all the splatter.
Went out again and captured the bog. First time is a bit off, but second hit shows the bog. Starts to go, then it bogs. I put a sharpie cap on the throttle for better visual sync. The terrible camera work didn't help, though. https://www.jalopyjournal.com/forum/media/bog.594775/
Something that's easy to try...remove the linkage connecting the two carbs. See how it behaves. here's a picture of a 750 holley, and a 450 holley, looking down. Compare to yours. I think you have way too much carb. See if you can find a single 4bbl top for the tunnel ram?
@squirrel , I agree that it's over cammed and over carb'ed. Just trying to make the best of it! A stock 1961 283 2 bbl is more than enough to go in this chassis. https://www.enginefacts.com/chevrolet283/ 1960 -1962 with 2 Barrel Carb HP: 170 @ 4200 rpm Tq: 275 @ 2200 rpm Compression: 8.5 I mentioned before that this weighs 2180 with my ~200 sitting in it. So 1980 pounds wet and running. It's the opposite of a sleeper, it's advertising more than it's really capable of. I wouldn't run it at WOT for a quarter mile until it's a lot more sorted. No legit track would let me in it's current state, either.
Hard to see clearly in the videos but the accel. pump springs look awful tight, the looser they are the more travel they have. So you might try loosening them up.
and I appreciate it, Jim. So I went out and pulled the squirters. 25 in both. Had the usual thing I was trying to avoid, dropped one of the washers down on the throttle plate, even with a rag tucked in mostly, under the choke plate. Pull the carb, of course one stud hung on the nut and walked out. Of course it was the one next to the throttle and accel pump. Got it off and didn't wash the washer off the blade. I knew both had spacers, but they are spread bore to straight bore adapters! WTF! Got the squirters back in and checked if the carbs fit without the spacers and they do. Less volume and fewer gaskets to cause issues! I will have to get shorter studs though, so it turned into the stop while apart I was trying to avoid. I got pics, but didn't caliper the throttle holes. I'll do that before reassembly. Carbs are sitting on the intake to avoid falling debris. Could use a couple washers and new cotters on the linkage. Otherwise it all went smooth. #25 squirters (no squirters listed in chart) spacer/adapter (?) Throttles (the chart says 1 and 9/16" is 600 CFM) without spacers.
I want to say Holley says to hold the throttle wide open and there should be 10 thou. clearance between the arm and the screw. I just loosen them up so they have full travel. Probably the number one thing I used to see back in the day was guys would tighten the nut down compressing the spring and take all the travel out of the pump.
Throttles are 1.560 = 1 9/16" Would have to disassemble to check venturi. Springs _ I agree with your spring set up. The calipers look wider, but that's due to depth of view.
Double checking on the spring adjustment, ran across this, which I will use. www.holley.com/blog/post/how_to_adjust_the_accelerator_pump_on_holley_carburetors/ So now I know it's not bigger than 600, pink cams and #25 squirters. I'll watch this and check other stuff. Hopefully I can avoid buying the master kit. That would get the alt mount and a few other bits and pieces. I'll also give everything a good cleaning and leave the spacers out on reassembly.
Pulled the front carb primary bowl off. Gaskets are the good Blue ones and didn't split. Main jets are #EDIT56. power valve was barely snug and is a 56. I got pics of the bleeds so I hope I can read them and compare to chart. EDIT pics are not useful. Will have to clean and retry. jet pic added.
The Jalopy Journal
